drivers/lightnvm/rrpc.c

   1 /*
   2  * Copyright (C) 2015 IT University of Copenhagen
   3  * Initial release: Matias Bjorling <m@bjorling.me>
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License version
   7  * 2 as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * Implementation of a Round-robin page-based Hybrid FTL for Open-channel SSDs.
  15  */
  16
  17 #include "rrpc.h"
  18
  19 static struct kmem_cache *rrpc_gcb_cache, *rrpc_rq_cache;
  20 static DECLARE_RWSEM(rrpc_lock);
  21
  22 static int rrpc_submit_io(struct rrpc *rrpc, struct bio *bio,
  23                                 struct nvm_rq *rqd, unsigned long flags);
  24
  25 #define rrpc_for_each_lun(rrpc, rlun, i) \
  26                 for ((i) = 0, rlun = &(rrpc)->luns[0]; \
  27                         (i) < (rrpc)->nr_luns; (i)++, rlun = &(rrpc)->luns[(i)])
  28
  29 static void rrpc_page_invalidate(struct rrpc *rrpc, struct rrpc_addr *a)
  30 {
  31         struct rrpc_block *rblk = a->rblk;
  32         unsigned int pg_offset;
  33
  34         lockdep_assert_held(&rrpc->rev_lock);
  35
  36         if (a->addr == ADDR_EMPTY || !rblk)
  37                 return;
  38
  39         spin_lock(&rblk->lock);
  40
  41         div_u64_rem(a->addr, rrpc->dev->pgs_per_blk, &pg_offset);
  42         WARN_ON(test_and_set_bit(pg_offset, rblk->invalid_pages));
  43         rblk->nr_invalid_pages++;
  44
  45         spin_unlock(&rblk->lock);
  46
  47         rrpc->rev_trans_map[a->addr - rrpc->poffset].addr = ADDR_EMPTY;
  48 }
  49
  50 static void rrpc_invalidate_range(struct rrpc *rrpc, sector_t slba,
  51                                                                 unsigned len)
  52 {
  53         sector_t i;
  54
  55         spin_lock(&rrpc->rev_lock);
  56         for (i = slba; i < slba + len; i++) {
  57                 struct rrpc_addr *gp = &rrpc->trans_map[i];
  58
  59                 rrpc_page_invalidate(rrpc, gp);
  60                 gp->rblk = NULL;
  61         }
  62         spin_unlock(&rrpc->rev_lock);
  63 }
  64
  65 static struct nvm_rq *rrpc_inflight_laddr_acquire(struct rrpc *rrpc,
  66                                         sector_t laddr, unsigned int pages)
  67 {
  68         struct nvm_rq *rqd;
  69         struct rrpc_inflight_rq *inf;
  70
  71         rqd = mempool_alloc(rrpc->rq_pool, GFP_ATOMIC);
  72         if (!rqd)
  73                 return ERR_PTR(-ENOMEM);
  74
  75         inf = rrpc_get_inflight_rq(rqd);
  76         if (rrpc_lock_laddr(rrpc, laddr, pages, inf)) {
  77                 mempool_free(rqd, rrpc->rq_pool);
  78                 return NULL;
  79         }
  80
  81         return rqd;
  82 }
  83
  84 static void rrpc_inflight_laddr_release(struct rrpc *rrpc, struct nvm_rq *rqd)
  85 {
  86         struct rrpc_inflight_rq *inf = rrpc_get_inflight_rq(rqd);
  87
  88         rrpc_unlock_laddr(rrpc, inf);
  89
  90         mempool_free(rqd, rrpc->rq_pool);
  91 }
  92
  93 static void rrpc_discard(struct rrpc *rrpc, struct bio *bio)
  94 {
  95         sector_t slba = bio->bi_iter.bi_sector / NR_PHY_IN_LOG;
  96         sector_t len = bio->bi_iter.bi_size / RRPC_EXPOSED_PAGE_SIZE;
  97         struct nvm_rq *rqd;
  98
  99         do {
 100                 rqd = rrpc_inflight_laddr_acquire(rrpc, slba, len);
 101                 schedule();
 102         } while (!rqd);
 103
 104         if (IS_ERR(rqd)) {
 105                 pr_err("rrpc: unable to acquire inflight IO\n");
 106                 bio_io_error(bio);
 107                 return;
 108         }
 109
 110         rrpc_invalidate_range(rrpc, slba, len);
 111         rrpc_inflight_laddr_release(rrpc, rqd);
 112 }
 113
 114 static int block_is_full(struct rrpc *rrpc, struct rrpc_block *rblk)
 115 {
 116         return (rblk->next_page == rrpc->dev->pgs_per_blk);
 117 }
 118
 119 static u64 block_to_addr(struct rrpc *rrpc, struct rrpc_block *rblk)
 120 {
 121         struct nvm_block *blk = rblk->parent;
 122
 123         return blk->id * rrpc->dev->pgs_per_blk;
 124 }
 125
 126 static struct ppa_addr linear_to_generic_addr(struct nvm_dev *dev,
 127                                                         struct ppa_addr r)
 128 {
 129         struct ppa_addr l;
 130         int secs, pgs, blks, luns;
 131         sector_t ppa = r.ppa;
 132
 133         l.ppa = 0;
 134
 135         div_u64_rem(ppa, dev->sec_per_pg, &secs);
 136         l.g.sec = secs;
 137
 138         sector_div(ppa, dev->sec_per_pg);
 139         div_u64_rem(ppa, dev->sec_per_blk, &pgs);
 140         l.g.pg = pgs;
 141
 142         sector_div(ppa, dev->pgs_per_blk);
 143         div_u64_rem(ppa, dev->blks_per_lun, &blks);
 144         l.g.blk = blks;
 145
 146         sector_div(ppa, dev->blks_per_lun);
 147         div_u64_rem(ppa, dev->luns_per_chnl, &luns);
 148         l.g.lun = luns;
 149
 150         sector_div(ppa, dev->luns_per_chnl);
 151         l.g.ch = ppa;
 152
 153         return l;
 154 }
 155
 156 static struct ppa_addr rrpc_ppa_to_gaddr(struct nvm_dev *dev, u64 addr)
 157 {
 158         struct ppa_addr paddr;
 159
 160         paddr.ppa = addr;
 161         return linear_to_generic_addr(dev, paddr);
 162 }
 163
 164 /* requires lun->lock taken */
 165 static void rrpc_set_lun_cur(struct rrpc_lun *rlun, struct rrpc_block *rblk)
 166 {
 167         struct rrpc *rrpc = rlun->rrpc;
 168
 169         BUG_ON(!rblk);
 170
 171         if (rlun->cur) {
 172                 spin_lock(&rlun->cur->lock);
 173                 WARN_ON(!block_is_full(rrpc, rlun->cur));
 174                 spin_unlock(&rlun->cur->lock);
 175         }
 176         rlun->cur = rblk;
 177 }
 178
 179 static struct rrpc_block *rrpc_get_blk(struct rrpc *rrpc, struct rrpc_lun *rlun,
 180                                                         unsigned long flags)
 181 {
 182         struct nvm_block *blk;
 183         struct rrpc_block *rblk;
 184
 185         blk = nvm_get_blk(rrpc->dev, rlun->parent, flags);
 186         if (!blk)
 187                 return NULL;
 188
 189         rblk = &rlun->blocks[blk->id];
 190         blk->priv = rblk;
 191
 192         bitmap_zero(rblk->invalid_pages, rrpc->dev->pgs_per_blk);
 193         rblk->next_page = 0;
 194         rblk->nr_invalid_pages = 0;
 195         atomic_set(&rblk->data_cmnt_size, 0);
 196
 197         return rblk;
 198 }
 199
 200 static void rrpc_put_blk(struct rrpc *rrpc, struct rrpc_block *rblk)
 201 {
 202         nvm_put_blk(rrpc->dev, rblk->parent);
 203 }
 204
 205 static void rrpc_put_blks(struct rrpc *rrpc)
 206 {
 207         struct rrpc_lun *rlun;
 208         int i;
 209
 210         for (i = 0; i < rrpc->nr_luns; i++) {
 211                 rlun = &rrpc->luns[i];
 212                 if (rlun->cur)
 213                         rrpc_put_blk(rrpc, rlun->cur);
 214                 if (rlun->gc_cur)
 215                         rrpc_put_blk(rrpc, rlun->gc_cur);
 216         }
 217 }
 218
 219 static struct rrpc_lun *get_next_lun(struct rrpc *rrpc)
 220 {
 221         int next = atomic_inc_return(&rrpc->next_lun);
 222
 223         return &rrpc->luns[next % rrpc->nr_luns];
 224 }
 225
 226 static void rrpc_gc_kick(struct rrpc *rrpc)
 227 {
 228         struct rrpc_lun *rlun;
 229         unsigned int i;
 230
 231         for (i = 0; i < rrpc->nr_luns; i++) {
 232                 rlun = &rrpc->luns[i];
 233                 queue_work(rrpc->krqd_wq, &rlun->ws_gc);
 234         }
 235 }
 236
 237 /*
 238  * timed GC every interval.
 239  */
 240 static void rrpc_gc_timer(unsigned long data)
 241 {
 242         struct rrpc *rrpc = (struct rrpc *)data;
 243
 244         rrpc_gc_kick(rrpc);
 245         mod_timer(&rrpc->gc_timer, jiffies + msecs_to_jiffies(10));
 246 }
 247
 248 static void rrpc_end_sync_bio(struct bio *bio)
 249 {
 250         struct completion *waiting = bio->bi_private;
 251
 252         if (bio->bi_error)
 253                 pr_err("nvm: gc request failed (%u).\n", bio->bi_error);
 254
 255         complete(waiting);
 256 }
 257
 258 /*
 259  * rrpc_move_valid_pages -- migrate live data off the block
 260  * @rrpc: the 'rrpc' structure
 261  * @block: the block from which to migrate live pages
 262  *
 263  * Description:
 264  *   GC algorithms may call this function to migrate remaining live
 265  *   pages off the block prior to erasing it. This function blocks
 266  *   further execution until the operation is complete.
 267  */
 268 static int rrpc_move_valid_pages(struct rrpc *rrpc, struct rrpc_block *rblk)
 269 {
 270         struct request_queue *q = rrpc->dev->q;
 271         struct rrpc_rev_addr *rev;
 272         struct nvm_rq *rqd;
 273         struct bio *bio;
 274         struct page *page;
 275         int slot;
 276         int nr_pgs_per_blk = rrpc->dev->pgs_per_blk;
 277         u64 phys_addr;
 278         DECLARE_COMPLETION_ONSTACK(wait);
 279
 280         if (bitmap_full(rblk->invalid_pages, nr_pgs_per_blk))
 281                 return 0;
 282
 283         bio = bio_alloc(GFP_NOIO, 1);
 284         if (!bio) {
 285                 pr_err("nvm: could not alloc bio to gc\n");
 286                 return -ENOMEM;
 287         }
 288
 289         page = mempool_alloc(rrpc->page_pool, GFP_NOIO);
 290
 291         while ((slot = find_first_zero_bit(rblk->invalid_pages,
 292                                             nr_pgs_per_blk)) < nr_pgs_per_blk) {
 293
 294                 /* Lock laddr */
 295                 phys_addr = (rblk->parent->id * nr_pgs_per_blk) + slot;
 296
 297 try:
 298                 spin_lock(&rrpc->rev_lock);
 299                 /* Get logical address from physical to logical table */
 300                 rev = &rrpc->rev_trans_map[phys_addr - rrpc->poffset];
 301                 /* already updated by previous regular write */
 302                 if (rev->addr == ADDR_EMPTY) {
 303                         spin_unlock(&rrpc->rev_lock);
 304                         continue;
 305                 }
 306
 307                 rqd = rrpc_inflight_laddr_acquire(rrpc, rev->addr, 1);
 308                 if (IS_ERR_OR_NULL(rqd)) {
 309                         spin_unlock(&rrpc->rev_lock);
 310                         schedule();
 311                         goto try;
 312                 }
 313
 314                 spin_unlock(&rrpc->rev_lock);
 315
 316                 /* Perform read to do GC */
 317                 bio->bi_iter.bi_sector = rrpc_get_sector(rev->addr);
 318                 bio->bi_rw = READ;
 319                 bio->bi_private = &wait;
 320                 bio->bi_end_io = rrpc_end_sync_bio;
 321
 322                 /* TODO: may fail when EXP_PG_SIZE > PAGE_SIZE */
 323                 bio_add_pc_page(q, bio, page, RRPC_EXPOSED_PAGE_SIZE, 0);
 324
 325                 if (rrpc_submit_io(rrpc, bio, rqd, NVM_IOTYPE_GC)) {
 326                         pr_err("rrpc: gc read failed.\n");
 327                         rrpc_inflight_laddr_release(rrpc, rqd);
 328                         goto finished;
 329                 }
 330                 wait_for_completion_io(&wait);
 331
 332                 bio_reset(bio);
 333                 reinit_completion(&wait);
 334
 335                 bio->bi_iter.bi_sector = rrpc_get_sector(rev->addr);
 336                 bio->bi_rw = WRITE;
 337                 bio->bi_private = &wait;
 338                 bio->bi_end_io = rrpc_end_sync_bio;
 339
 340                 bio_add_pc_page(q, bio, page, RRPC_EXPOSED_PAGE_SIZE, 0);
 341
 342                 /* turn the command around and write the data back to a new
 343                  * address
 344                  */
 345                 if (rrpc_submit_io(rrpc, bio, rqd, NVM_IOTYPE_GC)) {
 346                         pr_err("rrpc: gc write failed.\n");
 347                         rrpc_inflight_laddr_release(rrpc, rqd);
 348                         goto finished;
 349                 }
 350                 wait_for_completion_io(&wait);
 351
 352                 rrpc_inflight_laddr_release(rrpc, rqd);
 353
 354                 bio_reset(bio);
 355         }
 356
 357 finished:
 358         mempool_free(page, rrpc->page_pool);
 359         bio_put(bio);
 360
 361         if (!bitmap_full(rblk->invalid_pages, nr_pgs_per_blk)) {
 362                 pr_err("nvm: failed to garbage collect block\n");
 363                 return -EIO;
 364         }
 365
 366         return 0;
 367 }
 368
 369 static void rrpc_block_gc(struct work_struct *work)
 370 {
 371         struct rrpc_block_gc *gcb = container_of(work, struct rrpc_block_gc,
 372                                                                         ws_gc);
 373         struct rrpc *rrpc = gcb->rrpc;
 374         struct rrpc_block *rblk = gcb->rblk;
 375         struct nvm_dev *dev = rrpc->dev;
 376
 377         pr_debug("nvm: block '%lu' being reclaimed\n", rblk->parent->id);
 378
 379         if (rrpc_move_valid_pages(rrpc, rblk))
 380                 goto done;
 381
 382         nvm_erase_blk(dev, rblk->parent);
 383         rrpc_put_blk(rrpc, rblk);
 384 done:
 385         mempool_free(gcb, rrpc->gcb_pool);
 386 }
 387
 388 /* the block with highest number of invalid pages, will be in the beginning
 389  * of the list
 390  */
 391 static struct rrpc_block *rblock_max_invalid(struct rrpc_block *ra,
 392                                                         struct rrpc_block *rb)
 393 {
 394         if (ra->nr_invalid_pages == rb->nr_invalid_pages)
 395                 return ra;
 396
 397         return (ra->nr_invalid_pages < rb->nr_invalid_pages) ? rb : ra;
 398 }
 399
 400 /* linearly find the block with highest number of invalid pages
 401  * requires lun->lock
 402  */
 403 static struct rrpc_block *block_prio_find_max(struct rrpc_lun *rlun)
 404 {
 405         struct list_head *prio_list = &rlun->prio_list;
 406         struct rrpc_block *rblock, *max;
 407
 408         BUG_ON(list_empty(prio_list));
 409
 410         max = list_first_entry(prio_list, struct rrpc_block, prio);
 411         list_for_each_entry(rblock, prio_list, prio)
 412                 max = rblock_max_invalid(max, rblock);
 413
 414         return max;
 415 }
 416
 417 static void rrpc_lun_gc(struct work_struct *work)
 418 {
 419         struct rrpc_lun *rlun = container_of(work, struct rrpc_lun, ws_gc);
 420         struct rrpc *rrpc = rlun->rrpc;
 421         struct nvm_lun *lun = rlun->parent;
 422         struct rrpc_block_gc *gcb;
 423         unsigned int nr_blocks_need;
 424
 425         nr_blocks_need = rrpc->dev->blks_per_lun / GC_LIMIT_INVERSE;
 426
 427         if (nr_blocks_need < rrpc->nr_luns)
 428                 nr_blocks_need = rrpc->nr_luns;
 429
 430         spin_lock(&lun->lock);
 431         while (nr_blocks_need > lun->nr_free_blocks &&
 432                                         !list_empty(&rlun->prio_list)) {
 433                 struct rrpc_block *rblock = block_prio_find_max(rlun);
 434                 struct nvm_block *block = rblock->parent;
 435
 436                 if (!rblock->nr_invalid_pages)
 437                         break;
 438
 439                 list_del_init(&rblock->prio);
 440
 441                 BUG_ON(!block_is_full(rrpc, rblock));
 442
 443                 pr_debug("rrpc: selected block '%lu' for GC\n", block->id);
 444
 445                 gcb = mempool_alloc(rrpc->gcb_pool, GFP_ATOMIC);
 446                 if (!gcb)
 447                         break;
 448
 449                 gcb->rrpc = rrpc;
 450                 gcb->rblk = rblock;
 451                 INIT_WORK(&gcb->ws_gc, rrpc_block_gc);
 452
 453                 queue_work(rrpc->kgc_wq, &gcb->ws_gc);
 454
 455                 nr_blocks_need--;
 456         }
 457         spin_unlock(&lun->lock);
 458
 459         /* TODO: Hint that request queue can be started again */
 460 }
 461
 462 static void rrpc_gc_queue(struct work_struct *work)
 463 {
 464         struct rrpc_block_gc *gcb = container_of(work, struct rrpc_block_gc,
 465                                                                         ws_gc);
 466         struct rrpc *rrpc = gcb->rrpc;
 467         struct rrpc_block *rblk = gcb->rblk;
 468         struct nvm_lun *lun = rblk->parent->lun;
 469         struct rrpc_lun *rlun = &rrpc->luns[lun->id - rrpc->lun_offset];
 470
 471         spin_lock(&rlun->lock);
 472         list_add_tail(&rblk->prio, &rlun->prio_list);
 473         spin_unlock(&rlun->lock);
 474
 475         mempool_free(gcb, rrpc->gcb_pool);
 476         pr_debug("nvm: block '%lu' is full, allow GC (sched)\n",
 477                                                         rblk->parent->id);
 478 }
 479
 480 static const struct block_device_operations rrpc_fops = {
 481         .owner          = THIS_MODULE,
 482 };
 483
 484 static struct rrpc_lun *rrpc_get_lun_rr(struct rrpc *rrpc, int is_gc)
 485 {
 486         unsigned int i;
 487         struct rrpc_lun *rlun, *max_free;
 488
 489         if (!is_gc)
 490                 return get_next_lun(rrpc);
 491
 492         /* during GC, we don't care about RR, instead we want to make
 493          * sure that we maintain evenness between the block luns.
 494          */
 495         max_free = &rrpc->luns[0];
 496         /* prevent GC-ing lun from devouring pages of a lun with
 497          * little free blocks. We don't take the lock as we only need an
 498          * estimate.
 499          */
 500         rrpc_for_each_lun(rrpc, rlun, i) {
 501                 if (rlun->parent->nr_free_blocks >
 502                                         max_free->parent->nr_free_blocks)
 503                         max_free = rlun;
 504         }
 505
 506         return max_free;
 507 }
 508
 509 static struct rrpc_addr *rrpc_update_map(struct rrpc *rrpc, sector_t laddr,
 510                                         struct rrpc_block *rblk, u64 paddr)
 511 {
 512         struct rrpc_addr *gp;
 513         struct rrpc_rev_addr *rev;
 514
 515         BUG_ON(laddr >= rrpc->nr_pages);
 516
 517         gp = &rrpc->trans_map[laddr];
 518         spin_lock(&rrpc->rev_lock);
 519         if (gp->rblk)
 520                 rrpc_page_invalidate(rrpc, gp);
 521
 522         gp->addr = paddr;
 523         gp->rblk = rblk;
 524
 525         rev = &rrpc->rev_trans_map[gp->addr - rrpc->poffset];
 526         rev->addr = laddr;
 527         spin_unlock(&rrpc->rev_lock);
 528
 529         return gp;
 530 }
 531
 532 static u64 rrpc_alloc_addr(struct rrpc *rrpc, struct rrpc_block *rblk)
 533 {
 534         u64 addr = ADDR_EMPTY;
 535
 536         spin_lock(&rblk->lock);
 537         if (block_is_full(rrpc, rblk))
 538                 goto out;
 539
 540         addr = block_to_addr(rrpc, rblk) + rblk->next_page;
 541
 542         rblk->next_page++;
 543 out:
 544         spin_unlock(&rblk->lock);
 545         return addr;
 546 }
 547
 548 /* Simple round-robin Logical to physical address translation.
 549  *
 550  * Retrieve the mapping using the active append point. Then update the ap for
 551  * the next write to the disk.
 552  *
 553  * Returns rrpc_addr with the physical address and block. Remember to return to
 554  * rrpc->addr_cache when request is finished.
 555  */
 556 static struct rrpc_addr *rrpc_map_page(struct rrpc *rrpc, sector_t laddr,
 557                                                                 int is_gc)
 558 {
 559         struct rrpc_lun *rlun;
 560         struct rrpc_block *rblk;
 561         struct nvm_lun *lun;
 562         u64 paddr;
 563
 564         rlun = rrpc_get_lun_rr(rrpc, is_gc);
 565         lun = rlun->parent;
 566
 567         if (!is_gc && lun->nr_free_blocks < rrpc->nr_luns * 4)
 568                 return NULL;
 569
 570         spin_lock(&rlun->lock);
 571
 572         rblk = rlun->cur;
 573 retry:
 574         paddr = rrpc_alloc_addr(rrpc, rblk);
 575
 576         if (paddr == ADDR_EMPTY) {
 577                 rblk = rrpc_get_blk(rrpc, rlun, 0);
 578                 if (rblk) {
 579                         rrpc_set_lun_cur(rlun, rblk);
 580                         goto retry;
 581                 }
 582
 583                 if (is_gc) {
 584                         /* retry from emergency gc block */
 585                         paddr = rrpc_alloc_addr(rrpc, rlun->gc_cur);
 586                         if (paddr == ADDR_EMPTY) {
 587                                 rblk = rrpc_get_blk(rrpc, rlun, 1);
 588                                 if (!rblk) {
 589                                         pr_err("rrpc: no more blocks");
 590                                         goto err;
 591                                 }
 592
 593                                 rlun->gc_cur = rblk;
 594                                 paddr = rrpc_alloc_addr(rrpc, rlun->gc_cur);
 595                         }
 596                         rblk = rlun->gc_cur;
 597                 }
 598         }
 599
 600         spin_unlock(&rlun->lock);
 601         return rrpc_update_map(rrpc, laddr, rblk, paddr);
 602 err:
 603         spin_unlock(&rlun->lock);
 604         return NULL;
 605 }
 606
 607 static void rrpc_run_gc(struct rrpc *rrpc, struct rrpc_block *rblk)
 608 {
 609         struct rrpc_block_gc *gcb;
 610
 611         gcb = mempool_alloc(rrpc->gcb_pool, GFP_ATOMIC);
 612         if (!gcb) {
 613                 pr_err("rrpc: unable to queue block for gc.");
 614                 return;
 615         }
 616
 617         gcb->rrpc = rrpc;
 618         gcb->rblk = rblk;
 619
 620         INIT_WORK(&gcb->ws_gc, rrpc_gc_queue);
 621         queue_work(rrpc->kgc_wq, &gcb->ws_gc);
 622 }
 623
 624 static void rrpc_end_io_write(struct rrpc *rrpc, struct rrpc_rq *rrqd,
 625                                                 sector_t laddr, uint8_t npages)
 626 {
 627         struct rrpc_addr *p;
 628         struct rrpc_block *rblk;
 629         struct nvm_lun *lun;
 630         int cmnt_size, i;
 631
 632         for (i = 0; i < npages; i++) {
 633                 p = &rrpc->trans_map[laddr + i];
 634                 rblk = p->rblk;
 635                 lun = rblk->parent->lun;
 636
 637                 cmnt_size = atomic_inc_return(&rblk->data_cmnt_size);
 638                 if (unlikely(cmnt_size == rrpc->dev->pgs_per_blk))
 639                         rrpc_run_gc(rrpc, rblk);
 640         }
 641 }
 642
 643 static int rrpc_end_io(struct nvm_rq *rqd, int error)
 644 {
 645         struct rrpc *rrpc = container_of(rqd->ins, struct rrpc, instance);
 646         struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
 647         uint8_t npages = rqd->nr_pages;
 648         sector_t laddr = rrpc_get_laddr(rqd->bio) - npages;
 649
 650         if (bio_data_dir(rqd->bio) == WRITE)
 651                 rrpc_end_io_write(rrpc, rrqd, laddr, npages);
 652
 653         if (rrqd->flags & NVM_IOTYPE_GC)
 654                 return 0;
 655
 656         rrpc_unlock_rq(rrpc, rqd);
 657         bio_put(rqd->bio);
 658
 659         if (npages > 1)
 660                 nvm_dev_dma_free(rrpc->dev, rqd->ppa_list, rqd->dma_ppa_list);
 661         if (rqd->metadata)
 662                 nvm_dev_dma_free(rrpc->dev, rqd->metadata, rqd->dma_metadata);
 663
 664         mempool_free(rqd, rrpc->rq_pool);
 665
 666         return 0;
 667 }
 668
 669 static int rrpc_read_ppalist_rq(struct rrpc *rrpc, struct bio *bio,
 670                         struct nvm_rq *rqd, unsigned long flags, int npages)
 671 {
 672         struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
 673         struct rrpc_addr *gp;
 674         sector_t laddr = rrpc_get_laddr(bio);
 675         int is_gc = flags & NVM_IOTYPE_GC;
 676         int i;
 677
 678         if (!is_gc && rrpc_lock_rq(rrpc, bio, rqd)) {
 679                 nvm_dev_dma_free(rrpc->dev, rqd->ppa_list, rqd->dma_ppa_list);
 680                 return NVM_IO_REQUEUE;
 681         }
 682
 683         for (i = 0; i < npages; i++) {
 684                 /* We assume that mapping occurs at 4KB granularity */
 685                 BUG_ON(!(laddr + i >= 0 && laddr + i < rrpc->nr_pages));
 686                 gp = &rrpc->trans_map[laddr + i];
 687
 688                 if (gp->rblk) {
 689                         rqd->ppa_list[i] = rrpc_ppa_to_gaddr(rrpc->dev,
 690                                                                 gp->addr);
 691                 } else {
 692                         BUG_ON(is_gc);
 693                         rrpc_unlock_laddr(rrpc, r);
 694                         nvm_dev_dma_free(rrpc->dev, rqd->ppa_list,
 695                                                         rqd->dma_ppa_list);
 696                         return NVM_IO_DONE;
 697                 }
 698         }
 699
 700         rqd->opcode = NVM_OP_HBREAD;
 701
 702         return NVM_IO_OK;
 703 }
 704
 705 static int rrpc_read_rq(struct rrpc *rrpc, struct bio *bio, struct nvm_rq *rqd,
 706                                                         unsigned long flags)
 707 {
 708         struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
 709         int is_gc = flags & NVM_IOTYPE_GC;
 710         sector_t laddr = rrpc_get_laddr(bio);
 711         struct rrpc_addr *gp;
 712
 713         if (!is_gc && rrpc_lock_rq(rrpc, bio, rqd))
 714                 return NVM_IO_REQUEUE;
 715
 716         BUG_ON(!(laddr >= 0 && laddr < rrpc->nr_pages));
 717         gp = &rrpc->trans_map[laddr];
 718
 719         if (gp->rblk) {
 720                 rqd->ppa_addr = rrpc_ppa_to_gaddr(rrpc->dev, gp->addr);
 721         } else {
 722                 BUG_ON(is_gc);
 723                 rrpc_unlock_rq(rrpc, rqd);
 724                 return NVM_IO_DONE;
 725         }
 726
 727         rqd->opcode = NVM_OP_HBREAD;
 728         rrqd->addr = gp;
 729
 730         return NVM_IO_OK;
 731 }
 732
 733 static int rrpc_write_ppalist_rq(struct rrpc *rrpc, struct bio *bio,
 734                         struct nvm_rq *rqd, unsigned long flags, int npages)
 735 {
 736         struct rrpc_inflight_rq *r = rrpc_get_inflight_rq(rqd);
 737         struct rrpc_addr *p;
 738         sector_t laddr = rrpc_get_laddr(bio);
 739         int is_gc = flags & NVM_IOTYPE_GC;
 740         int i;
 741
 742         if (!is_gc && rrpc_lock_rq(rrpc, bio, rqd)) {
 743                 nvm_dev_dma_free(rrpc->dev, rqd->ppa_list, rqd->dma_ppa_list);
 744                 return NVM_IO_REQUEUE;
 745         }
 746
 747         for (i = 0; i < npages; i++) {
 748                 /* We assume that mapping occurs at 4KB granularity */
 749                 p = rrpc_map_page(rrpc, laddr + i, is_gc);
 750                 if (!p) {
 751                         BUG_ON(is_gc);
 752                         rrpc_unlock_laddr(rrpc, r);
 753                         nvm_dev_dma_free(rrpc->dev, rqd->ppa_list,
 754                                                         rqd->dma_ppa_list);
 755                         rrpc_gc_kick(rrpc);
 756                         return NVM_IO_REQUEUE;
 757                 }
 758
 759                 rqd->ppa_list[i] = rrpc_ppa_to_gaddr(rrpc->dev,
 760                                                                 p->addr);
 761         }
 762
 763         rqd->opcode = NVM_OP_HBWRITE;
 764
 765         return NVM_IO_OK;
 766 }
 767
 768 static int rrpc_write_rq(struct rrpc *rrpc, struct bio *bio,
 769                                 struct nvm_rq *rqd, unsigned long flags)
 770 {
 771         struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);
 772         struct rrpc_addr *p;
 773         int is_gc = flags & NVM_IOTYPE_GC;
 774         sector_t laddr = rrpc_get_laddr(bio);
 775
 776         if (!is_gc && rrpc_lock_rq(rrpc, bio, rqd))
 777                 return NVM_IO_REQUEUE;
 778
 779         p = rrpc_map_page(rrpc, laddr, is_gc);
 780         if (!p) {
 781                 BUG_ON(is_gc);
 782                 rrpc_unlock_rq(rrpc, rqd);
 783                 rrpc_gc_kick(rrpc);
 784                 return NVM_IO_REQUEUE;
 785         }
 786
 787         rqd->ppa_addr = rrpc_ppa_to_gaddr(rrpc->dev, p->addr);
 788         rqd->opcode = NVM_OP_HBWRITE;
 789         rrqd->addr = p;
 790
 791         return NVM_IO_OK;
 792 }
 793
 794 static int rrpc_setup_rq(struct rrpc *rrpc, struct bio *bio,
 795                         struct nvm_rq *rqd, unsigned long flags, uint8_t npages)
 796 {
 797         if (npages > 1) {
 798                 rqd->ppa_list = nvm_dev_dma_alloc(rrpc->dev, GFP_KERNEL,
 799                                                         &rqd->dma_ppa_list);
 800                 if (!rqd->ppa_list) {
 801                         pr_err("rrpc: not able to allocate ppa list\n");
 802                         return NVM_IO_ERR;
 803                 }
 804
 805                 if (bio_rw(bio) == WRITE)
 806                         return rrpc_write_ppalist_rq(rrpc, bio, rqd, flags,
 807                                                                         npages);
 808
 809                 return rrpc_read_ppalist_rq(rrpc, bio, rqd, flags, npages);
 810         }
 811
 812         if (bio_rw(bio) == WRITE)
 813                 return rrpc_write_rq(rrpc, bio, rqd, flags);
 814
 815         return rrpc_read_rq(rrpc, bio, rqd, flags);
 816 }
 817
 818 static int rrpc_submit_io(struct rrpc *rrpc, struct bio *bio,
 819                                 struct nvm_rq *rqd, unsigned long flags)
 820 {
 821         int err;
 822         struct rrpc_rq *rrq = nvm_rq_to_pdu(rqd);
 823         uint8_t nr_pages = rrpc_get_pages(bio);
 824         int bio_size = bio_sectors(bio) << 9;
 825
 826         if (bio_size < rrpc->dev->sec_size)
 827                 return NVM_IO_ERR;
 828         else if (bio_size > rrpc->dev->max_rq_size)
 829                 return NVM_IO_ERR;
 830
 831         err = rrpc_setup_rq(rrpc, bio, rqd, flags, nr_pages);
 832         if (err)
 833                 return err;
 834
 835         bio_get(bio);
 836         rqd->bio = bio;
 837         rqd->ins = &rrpc->instance;
 838         rqd->nr_pages = nr_pages;
 839         rrq->flags = flags;
 840
 841         err = nvm_submit_io(rrpc->dev, rqd);
 842         if (err) {
 843                 pr_err("rrpc: I/O submission failed: %d\n", err);
 844                 return NVM_IO_ERR;
 845         }
 846
 847         return NVM_IO_OK;
 848 }
 849
 850 static blk_qc_t rrpc_make_rq(struct request_queue *q, struct bio *bio)
 851 {
 852         struct rrpc *rrpc = q->queuedata;
 853         struct nvm_rq *rqd;
 854         int err;
 855
 856         if (bio->bi_rw & REQ_DISCARD) {
 857                 rrpc_discard(rrpc, bio);
 858                 return BLK_QC_T_NONE;
 859         }
 860
 861         rqd = mempool_alloc(rrpc->rq_pool, GFP_KERNEL);
 862         if (!rqd) {
 863                 pr_err_ratelimited("rrpc: not able to queue bio.");
 864                 bio_io_error(bio);
 865                 return BLK_QC_T_NONE;
 866         }
 867         memset(rqd, 0, sizeof(struct nvm_rq));
 868
 869         err = rrpc_submit_io(rrpc, bio, rqd, NVM_IOTYPE_NONE);
 870         switch (err) {
 871         case NVM_IO_OK:
 872                 return BLK_QC_T_NONE;
 873         case NVM_IO_ERR:
 874                 bio_io_error(bio);
 875                 break;
 876         case NVM_IO_DONE:
 877                 bio_endio(bio);
 878                 break;
 879         case NVM_IO_REQUEUE:
 880                 spin_lock(&rrpc->bio_lock);
 881                 bio_list_add(&rrpc->requeue_bios, bio);
 882                 spin_unlock(&rrpc->bio_lock);
 883                 queue_work(rrpc->kgc_wq, &rrpc->ws_requeue);
 884                 break;
 885         }
 886
 887         mempool_free(rqd, rrpc->rq_pool);
 888         return BLK_QC_T_NONE;
 889 }
 890
 891 static void rrpc_requeue(struct work_struct *work)
 892 {
 893         struct rrpc *rrpc = container_of(work, struct rrpc, ws_requeue);
 894         struct bio_list bios;
 895         struct bio *bio;
 896
 897         bio_list_init(&bios);
 898
 899         spin_lock(&rrpc->bio_lock);
 900         bio_list_merge(&bios, &rrpc->requeue_bios);
 901         bio_list_init(&rrpc->requeue_bios);
 902         spin_unlock(&rrpc->bio_lock);
 903
 904         while ((bio = bio_list_pop(&bios)))
 905                 rrpc_make_rq(rrpc->disk->queue, bio);
 906 }
 907
 908 static void rrpc_gc_free(struct rrpc *rrpc)
 909 {
 910         struct rrpc_lun *rlun;
 911         int i;
 912
 913         if (rrpc->krqd_wq)
 914                 destroy_workqueue(rrpc->krqd_wq);
 915
 916         if (rrpc->kgc_wq)
 917                 destroy_workqueue(rrpc->kgc_wq);
 918
 919         if (!rrpc->luns)
 920                 return;
 921
 922         for (i = 0; i < rrpc->nr_luns; i++) {
 923                 rlun = &rrpc->luns[i];
 924
 925                 if (!rlun->blocks)
 926                         break;
 927                 vfree(rlun->blocks);
 928         }
 929 }
 930
 931 static int rrpc_gc_init(struct rrpc *rrpc)
 932 {
 933         rrpc->krqd_wq = alloc_workqueue("rrpc-lun", WQ_MEM_RECLAIM|WQ_UNBOUND,
 934                                                                 rrpc->nr_luns);
 935         if (!rrpc->krqd_wq)
 936                 return -ENOMEM;
 937
 938         rrpc->kgc_wq = alloc_workqueue("rrpc-bg", WQ_MEM_RECLAIM, 1);
 939         if (!rrpc->kgc_wq)
 940                 return -ENOMEM;
 941
 942         setup_timer(&rrpc->gc_timer, rrpc_gc_timer, (unsigned long)rrpc);
 943
 944         return 0;
 945 }
 946
 947 static void rrpc_map_free(struct rrpc *rrpc)
 948 {
 949         vfree(rrpc->rev_trans_map);
 950         vfree(rrpc->trans_map);
 951 }
 952
 953 static int rrpc_l2p_update(u64 slba, u32 nlb, __le64 *entries, void *private)
 954 {
 955         struct rrpc *rrpc = (struct rrpc *)private;
 956         struct nvm_dev *dev = rrpc->dev;
 957         struct rrpc_addr *addr = rrpc->trans_map + slba;
 958         struct rrpc_rev_addr *raddr = rrpc->rev_trans_map;
 959         sector_t max_pages = dev->total_pages * (dev->sec_size >> 9);
 960         u64 elba = slba + nlb;
 961         u64 i;
 962
 963         if (unlikely(elba > dev->total_pages)) {
 964                 pr_err("nvm: L2P data from device is out of bounds!\n");
 965                 return -EINVAL;
 966         }
 967
 968         for (i = 0; i < nlb; i++) {
 969                 u64 pba = le64_to_cpu(entries[i]);
 970                 /* LNVM treats address-spaces as silos, LBA and PBA are
 971                  * equally large and zero-indexed.
 972                  */
 973                 if (unlikely(pba >= max_pages && pba != U64_MAX)) {
 974                         pr_err("nvm: L2P data entry is out of bounds!\n");
 975                         return -EINVAL;
 976                 }
 977
 978                 /* Address zero is a special one. The first page on a disk is
 979                  * protected. As it often holds internal device boot
 980                  * information.
 981                  */
 982                 if (!pba)
 983                         continue;
 984
 985                 addr[i].addr = pba;
 986                 raddr[pba].addr = slba + i;
 987         }
 988
 989         return 0;
 990 }
 991
 992 static int rrpc_map_init(struct rrpc *rrpc)
 993 {
 994         struct nvm_dev *dev = rrpc->dev;
 995         sector_t i;
 996         int ret;
 997
 998         rrpc->trans_map = vzalloc(sizeof(struct rrpc_addr) * rrpc->nr_pages);
 999         if (!rrpc->trans_map)
1000                 return -ENOMEM;
1001
1002         rrpc->rev_trans_map = vmalloc(sizeof(struct rrpc_rev_addr)
1003                                                         * rrpc->nr_pages);
1004         if (!rrpc->rev_trans_map)
1005                 return -ENOMEM;
1006
1007         for (i = 0; i < rrpc->nr_pages; i++) {
1008                 struct rrpc_addr *p = &rrpc->trans_map[i];
1009                 struct rrpc_rev_addr *r = &rrpc->rev_trans_map[i];
1010
1011                 p->addr = ADDR_EMPTY;
1012                 r->addr = ADDR_EMPTY;
1013         }
1014
1015         if (!dev->ops->get_l2p_tbl)
1016                 return 0;
1017
1018         /* Bring up the mapping table from device */
1019         ret = dev->ops->get_l2p_tbl(dev, 0, dev->total_pages,
1020                                                         rrpc_l2p_update, rrpc);
1021         if (ret) {
1022                 pr_err("nvm: rrpc: could not read L2P table.\n");
1023                 return -EINVAL;
1024         }
1025
1026         return 0;
1027 }
1028
1029
1030 /* Minimum pages needed within a lun */
1031 #define PAGE_POOL_SIZE 16
1032 #define ADDR_POOL_SIZE 64
1033
1034 static int rrpc_core_init(struct rrpc *rrpc)
1035 {
1036         down_write(&rrpc_lock);
1037         if (!rrpc_gcb_cache) {
1038                 rrpc_gcb_cache = kmem_cache_create("rrpc_gcb",
1039                                 sizeof(struct rrpc_block_gc), 0, 0, NULL);
1040                 if (!rrpc_gcb_cache) {
1041                         up_write(&rrpc_lock);
1042                         return -ENOMEM;
1043                 }
1044
1045                 rrpc_rq_cache = kmem_cache_create("rrpc_rq",
1046                                 sizeof(struct nvm_rq) + sizeof(struct rrpc_rq),
1047                                 0, 0, NULL);
1048                 if (!rrpc_rq_cache) {
1049                         kmem_cache_destroy(rrpc_gcb_cache);
1050                         up_write(&rrpc_lock);
1051                         return -ENOMEM;
1052                 }
1053         }
1054         up_write(&rrpc_lock);
1055
1056         rrpc->page_pool = mempool_create_page_pool(PAGE_POOL_SIZE, 0);
1057         if (!rrpc->page_pool)
1058                 return -ENOMEM;
1059
1060         rrpc->gcb_pool = mempool_create_slab_pool(rrpc->dev->nr_luns,
1061                                                                 rrpc_gcb_cache);
1062         if (!rrpc->gcb_pool)
1063                 return -ENOMEM;
1064
1065         rrpc->rq_pool = mempool_create_slab_pool(64, rrpc_rq_cache);
1066         if (!rrpc->rq_pool)
1067                 return -ENOMEM;
1068
1069         spin_lock_init(&rrpc->inflights.lock);
1070         INIT_LIST_HEAD(&rrpc->inflights.reqs);
1071
1072         return 0;
1073 }
1074
1075 static void rrpc_core_free(struct rrpc *rrpc)
1076 {
1077         mempool_destroy(rrpc->page_pool);
1078         mempool_destroy(rrpc->gcb_pool);
1079         mempool_destroy(rrpc->rq_pool);
1080 }
1081
1082 static void rrpc_luns_free(struct rrpc *rrpc)
1083 {
1084         kfree(rrpc->luns);
1085 }
1086
1087 static int rrpc_luns_init(struct rrpc *rrpc, int lun_begin, int lun_end)
1088 {
1089         struct nvm_dev *dev = rrpc->dev;
1090         struct rrpc_lun *rlun;
1091         int i, j;
1092
1093         spin_lock_init(&rrpc->rev_lock);
1094
1095         rrpc->luns = kcalloc(rrpc->nr_luns, sizeof(struct rrpc_lun),
1096                                                                 GFP_KERNEL);
1097         if (!rrpc->luns)
1098                 return -ENOMEM;
1099
1100         /* 1:1 mapping */
1101         for (i = 0; i < rrpc->nr_luns; i++) {
1102                 struct nvm_lun *lun = dev->mt->get_lun(dev, lun_begin + i);
1103
1104                 if (dev->pgs_per_blk >
1105                                 MAX_INVALID_PAGES_STORAGE * BITS_PER_LONG) {
1106                         pr_err("rrpc: number of pages per block too high.");
1107                         goto err;
1108                 }
1109
1110                 rlun = &rrpc->luns[i];
1111                 rlun->rrpc = rrpc;
1112                 rlun->parent = lun;
1113                 INIT_LIST_HEAD(&rlun->prio_list);
1114                 INIT_WORK(&rlun->ws_gc, rrpc_lun_gc);
1115                 spin_lock_init(&rlun->lock);
1116
1117                 rrpc->total_blocks += dev->blks_per_lun;
1118                 rrpc->nr_pages += dev->sec_per_lun;
1119
1120                 rlun->blocks = vzalloc(sizeof(struct rrpc_block) *
1121                                                 rrpc->dev->blks_per_lun);
1122                 if (!rlun->blocks)
1123                         goto err;
1124
1125                 for (j = 0; j < rrpc->dev->blks_per_lun; j++) {
1126                         struct rrpc_block *rblk = &rlun->blocks[j];
1127                         struct nvm_block *blk = &lun->blocks[j];
1128
1129                         rblk->parent = blk;
1130                         INIT_LIST_HEAD(&rblk->prio);
1131                         spin_lock_init(&rblk->lock);
1132                 }
1133         }
1134
1135         return 0;
1136 err:
1137         return -ENOMEM;
1138 }
1139
1140 static void rrpc_free(struct rrpc *rrpc)
1141 {
1142         rrpc_gc_free(rrpc);
1143         rrpc_map_free(rrpc);
1144         rrpc_core_free(rrpc);
1145         rrpc_luns_free(rrpc);
1146
1147         kfree(rrpc);
1148 }
1149
1150 static void rrpc_exit(void *private)
1151 {
1152         struct rrpc *rrpc = private;
1153
1154         del_timer(&rrpc->gc_timer);
1155
1156         flush_workqueue(rrpc->krqd_wq);
1157         flush_workqueue(rrpc->kgc_wq);
1158
1159         rrpc_free(rrpc);
1160 }
1161
1162 static sector_t rrpc_capacity(void *private)
1163 {
1164         struct rrpc *rrpc = private;
1165         struct nvm_dev *dev = rrpc->dev;
1166         sector_t reserved, provisioned;
1167
1168         /* cur, gc, and two emergency blocks for each lun */
1169         reserved = rrpc->nr_luns * dev->max_pages_per_blk * 4;
1170         provisioned = rrpc->nr_pages - reserved;
1171
1172         if (reserved > rrpc->nr_pages) {
1173                 pr_err("rrpc: not enough space available to expose storage.\n");
1174                 return 0;
1175         }
1176
1177         sector_div(provisioned, 10);
1178         return provisioned * 9 * NR_PHY_IN_LOG;
1179 }
1180
1181 /*
1182  * Looks up the logical address from reverse trans map and check if its valid by
1183  * comparing the logical to physical address with the physical address.
1184  * Returns 0 on free, otherwise 1 if in use
1185  */
1186 static void rrpc_block_map_update(struct rrpc *rrpc, struct rrpc_block *rblk)
1187 {
1188         struct nvm_dev *dev = rrpc->dev;
1189         int offset;
1190         struct rrpc_addr *laddr;
1191         u64 paddr, pladdr;
1192
1193         for (offset = 0; offset < dev->pgs_per_blk; offset++) {
1194                 paddr = block_to_addr(rrpc, rblk) + offset;
1195
1196                 pladdr = rrpc->rev_trans_map[paddr].addr;
1197                 if (pladdr == ADDR_EMPTY)
1198                         continue;
1199
1200                 laddr = &rrpc->trans_map[pladdr];
1201
1202                 if (paddr == laddr->addr) {
1203                         laddr->rblk = rblk;
1204                 } else {
1205                         set_bit(offset, rblk->invalid_pages);
1206                         rblk->nr_invalid_pages++;
1207                 }
1208         }
1209 }
1210
1211 static int rrpc_blocks_init(struct rrpc *rrpc)
1212 {
1213         struct rrpc_lun *rlun;
1214         struct rrpc_block *rblk;
1215         int lun_iter, blk_iter;
1216
1217         for (lun_iter = 0; lun_iter < rrpc->nr_luns; lun_iter++) {
1218                 rlun = &rrpc->luns[lun_iter];
1219
1220                 for (blk_iter = 0; blk_iter < rrpc->dev->blks_per_lun;
1221                                                                 blk_iter++) {
1222                         rblk = &rlun->blocks[blk_iter];
1223                         rrpc_block_map_update(rrpc, rblk);
1224                 }
1225         }
1226
1227         return 0;
1228 }
1229
1230 static int rrpc_luns_configure(struct rrpc *rrpc)
1231 {
1232         struct rrpc_lun *rlun;
1233         struct rrpc_block *rblk;
1234         int i;
1235
1236         for (i = 0; i < rrpc->nr_luns; i++) {
1237                 rlun = &rrpc->luns[i];
1238
1239                 rblk = rrpc_get_blk(rrpc, rlun, 0);
1240                 if (!rblk)
1241                         goto err;
1242
1243                 rrpc_set_lun_cur(rlun, rblk);
1244
1245                 /* Emergency gc block */
1246                 rblk = rrpc_get_blk(rrpc, rlun, 1);
1247                 if (!rblk)
1248                         goto err;
1249                 rlun->gc_cur = rblk;
1250         }
1251
1252         return 0;
1253 err:
1254         rrpc_put_blks(rrpc);
1255         return -EINVAL;
1256 }
1257
1258 static struct nvm_tgt_type tt_rrpc;
1259
1260 static void *rrpc_init(struct nvm_dev *dev, struct gendisk *tdisk,
1261                                                 int lun_begin, int lun_end)
1262 {
1263         struct request_queue *bqueue = dev->q;
1264         struct request_queue *tqueue = tdisk->queue;
1265         struct rrpc *rrpc;
1266         int ret;
1267
1268         if (!(dev->identity.dom & NVM_RSP_L2P)) {
1269                 pr_err("nvm: rrpc: device does not support l2p (%x)\n",
1270                                                         dev->identity.dom);
1271                 return ERR_PTR(-EINVAL);
1272         }
1273
1274         rrpc = kzalloc(sizeof(struct rrpc), GFP_KERNEL);
1275         if (!rrpc)
1276                 return ERR_PTR(-ENOMEM);
1277
1278         rrpc->instance.tt = &tt_rrpc;
1279         rrpc->dev = dev;
1280         rrpc->disk = tdisk;
1281
1282         bio_list_init(&rrpc->requeue_bios);
1283         spin_lock_init(&rrpc->bio_lock);
1284         INIT_WORK(&rrpc->ws_requeue, rrpc_requeue);
1285
1286         rrpc->nr_luns = lun_end - lun_begin + 1;
1287
1288         /* simple round-robin strategy */
1289         atomic_set(&rrpc->next_lun, -1);
1290
1291         ret = rrpc_luns_init(rrpc, lun_begin, lun_end);
1292         if (ret) {
1293                 pr_err("nvm: rrpc: could not initialize luns\n");
1294                 goto err;
1295         }
1296
1297         rrpc->poffset = dev->sec_per_lun * lun_begin;
1298         rrpc->lun_offset = lun_begin;
1299
1300         ret = rrpc_core_init(rrpc);
1301         if (ret) {
1302                 pr_err("nvm: rrpc: could not initialize core\n");
1303                 goto err;
1304         }
1305
1306         ret = rrpc_map_init(rrpc);
1307         if (ret) {
1308                 pr_err("nvm: rrpc: could not initialize maps\n");
1309                 goto err;
1310         }
1311
1312         ret = rrpc_blocks_init(rrpc);
1313         if (ret) {
1314                 pr_err("nvm: rrpc: could not initialize state for blocks\n");
1315                 goto err;
1316         }
1317
1318         ret = rrpc_luns_configure(rrpc);
1319         if (ret) {
1320                 pr_err("nvm: rrpc: not enough blocks available in LUNs.\n");
1321                 goto err;
1322         }
1323
1324         ret = rrpc_gc_init(rrpc);
1325         if (ret) {
1326                 pr_err("nvm: rrpc: could not initialize gc\n");
1327                 goto err;
1328         }
1329
1330         /* inherit the size from the underlying device */
1331         blk_queue_logical_block_size(tqueue, queue_physical_block_size(bqueue));
1332         blk_queue_max_hw_sectors(tqueue, queue_max_hw_sectors(bqueue));
1333
1334         pr_info("nvm: rrpc initialized with %u luns and %llu pages.\n",
1335                         rrpc->nr_luns, (unsigned long long)rrpc->nr_pages);
1336
1337         mod_timer(&rrpc->gc_timer, jiffies + msecs_to_jiffies(10));
1338
1339         return rrpc;
1340 err:
1341         rrpc_free(rrpc);
1342         return ERR_PTR(ret);
1343 }
1344
1345 /* round robin, page-based FTL, and cost-based GC */
1346 static struct nvm_tgt_type tt_rrpc = {
1347         .name           = "rrpc",
1348         .version        = {1, 0, 0},
1349
1350         .make_rq        = rrpc_make_rq,
1351         .capacity       = rrpc_capacity,
1352         .end_io         = rrpc_end_io,
1353
1354         .init           = rrpc_init,
1355         .exit           = rrpc_exit,
1356 };
1357
1358 static int __init rrpc_module_init(void)
1359 {
1360         return nvm_register_target(&tt_rrpc);
1361 }
1362
1363 static void rrpc_module_exit(void)
1364 {
1365         nvm_unregister_target(&tt_rrpc);
1366 }
1367
1368 module_init(rrpc_module_init);
1369 module_exit(rrpc_module_exit);
1370 MODULE_LICENSE("GPL v2");
1371 MODULE_DESCRIPTION("Block-Device Target for Open-Channel SSDs");